src/sim/dvfs_handler.cc

   1 /*
   2  * Copyright (c) 2013-2014 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Vasileios Spiliopoulos
  38  *          Akash Bagdia
  39  *          Stephan Diestelhorst
  40  */
  41
  42 #include "sim/dvfs_handler.hh"
  43
  44 #include <set>
  45 #include <utility>
  46
  47 #include "base/misc.hh"
  48 #include "base/trace.hh"
  49 #include "debug/DVFS.hh"
  50 #include "params/DVFSHandler.hh"
  51 #include "sim/clock_domain.hh"
  52 #include "sim/eventq_impl.hh"
  53 #include "sim/stat_control.hh"
  54 #include "sim/voltage_domain.hh"
  55
  56 //
  57 //
  58 // DVFSHandler methods implementation
  59 //
  60
  61 DVFSHandler::DVFSHandler(const Params *p)
  62     : SimObject(p),
  63       sysClkDomain(p->sys_clk_domain),
  64       enableHandler(p->enable),
  65       _transLatency(p->transition_latency)
  66 {
  67     // Check supplied list of domains for sanity and add them to the
  68     // domain ID -> domain* hash
  69     for (auto dit = p->domains.begin(); dit != p->domains.end(); ++dit) {
  70         SrcClockDomain *d = *dit;
  71         DomainID domain_id = d->domainID();
  72
  73         fatal_if(sysClkDomain == d, "DVFS: Domain config list has a "\
  74                  "system clk domain entry");
  75         fatal_if(domain_id == SrcClockDomain::emptyDomainID,
  76                  "DVFS: Controlled domain %s needs to have a properly "\
  77                  " assigned ID.\n", d->name());
  78
  79         auto entry = std::make_pair(domain_id, d);
  80         bool new_elem = domains.insert(entry).second;
  81         fatal_if(!new_elem, "DVFS: Domain %s with ID %d does not have a "\
  82                  "unique ID.\n", d->name(), domain_id);
  83
  84         // Create a dedicated event slot per known domain ID
  85         UpdateEvent *event = &updatePerfLevelEvents[domain_id];
  86         event->domainIDToSet = d->domainID();
  87
  88         // Add domain ID to the list of domains
  89         domainIDList.push_back(d->domainID());
  90     }
  91     UpdateEvent::dvfsHandler = this;
  92 }
  93
  94 DVFSHandler *DVFSHandler::UpdateEvent::dvfsHandler;
  95
  96 DVFSHandler::DomainID
  97 DVFSHandler::domainID(uint32_t index) const
  98 {
  99     fatal_if(index >= numDomains(), "DVFS: Requested index out of "\
 100              "bound, max value %d\n", (domainIDList.size() - 1));
 101
 102     assert(domains.find(domainIDList[index]) != domains.end());
 103
 104     return domainIDList[index];
 105 }
 106
 107 bool
 108 DVFSHandler::validDomainID(DomainID domain_id) const
 109 {
 110     assert(isEnabled());
 111     // This is ensure that the domain id as requested by the software is
 112     // availabe in the handler.
 113     if (domains.find(domain_id) != domains.end())
 114         return true;
 115     warn("DVFS: invalid domain ID %d, the DVFS handler does not handle this "\
 116          "domain\n", domain_id);
 117     return false;
 118 }
 119
 120 bool
 121 DVFSHandler::perfLevel(DomainID domain_id, PerfLevel perf_level)
 122 {
 123     assert(isEnabled());
 124
 125     DPRINTF(DVFS, "DVFS: setPerfLevel domain %d -> %d\n", domain_id, perf_level);
 126
 127     auto d = findDomain(domain_id);
 128     if (!d->validPerfLevel(perf_level)) {
 129         warn("DVFS: invalid performance level %d for domain ID %d, request "\
 130              "ignored\n", perf_level, domain_id);
 131         return false;
 132     }
 133
 134     UpdateEvent *update_event = &updatePerfLevelEvents[domain_id];
 135     // Drop an old DVFS change request once we have established that this is a
 136     // reasonable request
 137     if (update_event->scheduled()) {
 138         DPRINTF(DVFS, "DVFS: Overwriting the previous DVFS event.\n");
 139         deschedule(update_event);
 140     }
 141
 142     update_event->perfLevelToSet = perf_level;
 143
 144     // State changes that restore to the current state (and / or overwrite a not
 145     // yet completed in-flight request) will be squashed
 146     if (d->perfLevel() == perf_level) {
 147         DPRINTF(DVFS, "DVFS: Ignoring ineffective performance level change "\
 148                 "%d -> %d\n", d->perfLevel(), perf_level);
 149         return false;
 150     }
 151
 152     // At this point, a new transition will certainly take place -> schedule
 153     Tick when = curTick() + _transLatency;
 154     DPRINTF(DVFS, "DVFS: Update for perf event scheduled for %ld\n", when);
 155
 156     schedule(update_event, when);
 157     return true;
 158 }
 159
 160 void
 161 DVFSHandler::UpdateEvent::updatePerfLevel()
 162 {
 163     // Perform explicit stats dump for power estimation before performance
 164     // level migration
 165     Stats::dump();
 166     Stats::reset();
 167
 168     // Update the performance level in the clock domain
 169     auto d = dvfsHandler->findDomain(domainIDToSet);
 170     assert(d->perfLevel() != perfLevelToSet);
 171
 172     d->perfLevel(perfLevelToSet);
 173 }
 174
 175 double
 176 DVFSHandler::voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
 177 {
 178     VoltageDomain *d = findDomain(domain_id)->voltageDomain();
 179     assert(d);
 180     PerfLevel n = d->numVoltages();
 181     if (perf_level < n)
 182         return d->voltage(perf_level);
 183
 184     // Request outside of the range of the voltage domain
 185     if (n == 1) {
 186         DPRINTF(DVFS, "DVFS: Request for perf-level %i for single-point "\
 187                 "voltage domain %s.  Returning voltage at level 0: %.2f "\
 188                 "V\n", perf_level, d->name(), d->voltage(0));
 189         // Special case for single point voltage domain -> same voltage for
 190         // all points
 191         return d->voltage(0);
 192     }
 193
 194     warn("DVFSHandler %s reads illegal voltage level %u from "\
 195          "VoltageDomain %s. Returning 0 V\n", name(), perf_level, d->name());
 196     return 0.;
 197 }
 198
 199 void
 200 DVFSHandler::serialize(CheckpointOut &cp) const
 201 {
 202     //This is to ensure that the handler status is maintained during the
 203     //entire simulation run and not changed from command line during checkpoint
 204     //and restore
 205     SERIALIZE_SCALAR(enableHandler);
 206
 207     // Pull out the hashed data structure into easy-to-serialise arrays;
 208     // ensuring that the data associated with any pending update event is saved
 209     std::vector<DomainID> domain_ids;
 210     std::vector<PerfLevel> perf_levels;
 211     std::vector<Tick> whens;
 212     for (const auto &ev_pair : updatePerfLevelEvents) {
 213         DomainID id = ev_pair.first;
 214         const UpdateEvent *event = &ev_pair.second;
 215
 216         assert(id == event->domainIDToSet);
 217         domain_ids.push_back(id);
 218         perf_levels.push_back(event->perfLevelToSet);
 219         whens.push_back(event->scheduled() ? event->when() : 0);
 220     }
 221     SERIALIZE_CONTAINER(domain_ids);
 222     SERIALIZE_CONTAINER(perf_levels);
 223     SERIALIZE_CONTAINER(whens);
 224 }
 225
 226 void
 227 DVFSHandler::unserialize(CheckpointIn &cp)
 228 {
 229     bool temp = enableHandler;
 230
 231     UNSERIALIZE_SCALAR(enableHandler);
 232
 233     if (temp != enableHandler) {
 234         warn("DVFS: Forcing enable handler status to unserialized value of %d",
 235              enableHandler);
 236     }
 237
 238     // Reconstruct the map of domain IDs and their scheduled events
 239     std::vector<DomainID> domain_ids;
 240     std::vector<PerfLevel> perf_levels;
 241     std::vector<Tick> whens;
 242     UNSERIALIZE_CONTAINER(domain_ids);
 243     UNSERIALIZE_CONTAINER(perf_levels);
 244     UNSERIALIZE_CONTAINER(whens);
 245
 246     for (size_t i = 0; i < domain_ids.size(); ++i) {;
 247         UpdateEvent *event = &updatePerfLevelEvents[domain_ids[i]];
 248
 249         event->domainIDToSet = domain_ids[i];
 250         event->perfLevelToSet = perf_levels[i];
 251
 252         // Schedule all previously scheduled events
 253         if (whens[i])
 254             schedule(event, whens[i]);
 255     }
 256     UpdateEvent::dvfsHandler = this;
 257 }
 258
 259 DVFSHandler*
 260 DVFSHandlerParams::create()
 261 {
 262     return new DVFSHandler(this);
 263 }